This invention related to electronic musical instruments using time division multiplex signal trains for carrying musical data to re-create a performance that has been previously recorded on paper rolls, metal rolls, discs, etc. and, more especially, the so-called reproducing piano. Of these, a number gained widespread fame in the art, such as the Welte Mignon which, by means of a special recording device, the exact playing technique of famous artists could be captured on a paper roll. By means of sophisticated expression devices, the Welte Mignon piano could re-enact every moment, every nuance and every tonal shading of the performing artist (see PTM Magazine of February, 1969). Two American made types, the Ampico and the Duo-Art dominated the market in the United States and hence, there is a large number of roll music for these instruments in existence and some collectors have vast libraries of such recorded music. However, in each of the expression devices it is necessary to split the bass and treble expresion points so as to play expression music generated from these different sources. One source, the Welte, requires the split to be between notes 43 and 44, another, the Duo-Art, requires the split to be between 44 and 45, and still another, the Ampico, requires the split to be between notes 46 and 47. Thus, the problem solved by the present invention is to provide an electronic system which will recognize which of the sources is being played and automatically adapt the playback system of an electronic player piano to accommodate all of these various sources without difficulty. The invention is incorporated into a prior art electronic player piano system of the type disclosed in the above-identified applications as well as in the "Service Manual" for Teledyne Piano Recorder/Player Model PP-1, Assembly No. 3288" ATL 3263, a publication of the assignee hereof, published in October, 1975.